What does it mean to override a method? The original question is, can a subclass override the methods of its superclass?

Say you have a class ParentClass and it has a method SpiffyMethod.
And you create a subclass SubClass of ParentClass.
If you do not explicitly put SpiffyMethod into SubClass, and call SpiffyMethod from that subclass, it will use the SpiffyMethod from ParentClass.
However, if you DO explicitly code out a method SpiffyMethod inside SubClass it will "override" the method from ParentClass and when you call SpiffyMethod from SubClass, it will use it's own SpiffyMethod instead of the parents.
Basically, override just means "use my own instead of what I inherited from my parent class". A subclass can use whatever methods the parent provided, or provide new code (override) any method you want.